It should be noted that reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general knowledge in the art.
Graders have been used for many years in construction, mining, farming and road maintenance to displace and level material on the ground such as soil or snow in order to create a smooth, flat surface.
Graders generally comprise a chassis, two or three axles with wheels on which the grader can move and are self-propelled by an engine. Graders typically have a cab which houses the controls for the machine which can be operated by a person inside the cab. In any arrangement a grader will have at least one long blade which is located on the underside of the grader to contact the ground and scrape, clear or grade the surface of the ground. The blade is secured to the grader by a blade assembly which is usually located between two of the axles of the grader. However, the blade assembly may also be located at the very front of the grader, i.e. in front of the front axle.
At least one end of the blade can be lowered and raised so that the blade can be used to create level or angled ground surfaces. In use the blade is set to the desired position and then the grader is propelled forward so that the blade clears and levels the ground material to form a smooth, flat surface according to the angle of the blade. Furthermore, the blade assembly of most graders can also be adjusted within the horizontal plane so that the blade is not perpendicular to the direction of movement but rather advances through the ground material at an angle respective to the direction of movement.
Operation of the blade assemblies of graders typically involves rotational gears which turn the blade to the required angle respective to the direction of movement of the grader and hydraulic rams which lift the blade to the required height and grading angle.
During use, the blade is subject to significant and variable forces as it is moved through the ground material and accordingly, the grader and the blade can shudder and move during use. This is undesirable as it can result in the blade wobbling and moving over the ground creating an uneven surface. Guide blocks and bearing plates have been used to cushion the joints between moving parts of the blade assembly in order to absorb the forces experienced by the assembly during use. The guide blocks and bearing plates thereby remove the wobble and shudder from the assembly and maintain the accuracy of movement and operation of the blade.
However, the forces absorbed by the guide blocks and bearing plates cause them to wear which loosens the contact between the moving parts of the blade assembly. Accordingly, this introduces error to the turning circle and height of the blade resulting in reduced accuracy of adjustment of the blade position and reduced quality of the graded surface. Although the error is relatively small, modern earth moving operations require close accuracy and the guide blocks and bearing plates have to be replaced on a regular basis. This generally is performed by a qualified technician to ensure the location of the new wear pads meet manufacturer's specifications and can result in a full day of operational downtime. Therefore, it is not only time consuming but can be a costly task.
Accordingly, it would be advantageous of the present invention to provide a contrivance which ameliorates the disadvantages set forth above or at least provides an alternative to the prior art.